public class example03{
        public static void main(String[] args){
            int i = 20;
            long l = i;
            float f =l;
            double d=f;
            System.out.println("long类型变量l:"+l);
            System.out.println("float类型变量f:"+f);
            System.out.println("double类型变量d:"+d);
        }
}
